Telephone-exchange system



Apr. 3, "1%23. 1,450,564 F. M. SLOUGH TELEPHONE EXCHANGE SYS TEM FiledJan. 24, 1918 5 sheets-sheet 1 l i r 1' i i Apr fi. 1923. 1,450,564

F. M. SLOUGH TELEPHONE EXCHANGE SYSTEM Filed Jan. 34, 1918 5sheets-sheet 2 I N VEN TOR.

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Apr. 3, m3. 1,4505% F. M. S LOUG H TELEPHONE EXCHANGE SYSTEM Filed Jan.24, 1918 5 sheets-sheet 5 INVEN TGR @MMK Ar. 3; wzs. 1,4565% F. M. SLOUGH TELEPHONE EXCHANGE SYSTEM Filed Jan. 24, 1918 v5 sheets-sheet 4INVENTOR Apr. 3, 1923.

F. M. SLOUGH TELEPHONE EXCHANGE SYSTEM Filed Jan. 24, 1918 l lll H'INVENTOR www. f

Patented Apr. 3, 1923.

FRANK M. SLOUGH, OF ROCHESTER, NEW YORK, ASSIGNOR TO THE STROMBERG-;CARLSON TELEPHONE MANUFACTURING COMPANY, OF ROCHESTER, NEW

YORK, A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed January 24, 1918.

T 0 all whom it may concern.

Be it known that l, FRANK M. SLoUen, a citizen of the United States,residing "at Rochester, in the county of i\1oIi1'0e and State of NewYork, have invented a certain newand uset'ul Improvement in Telephone-Exchange Systems, of which the following is a full, concise, and exactdescription.

This invention relates to telephone exchange systems, and moreparticularly to that type of exchange systems in which calls areautomatically extended by mechanical means to different idle callreceiving apparatus.

()ne of its objects is to provide for the automatic distribution ofincoming calls to different operators positions in a manual switchboard,the distribution being in rotation, that is, calls will come in to callreceiving. circuits one after another in a given order not departingfrom this, unless some ot' the call receiving; circuits are manuallydisabled as will be described later.

Another of the objects of the invention is to provide a conversationalcircuit from the calling subscribers line to the operators callextending apparatus independent of the call receiving apparatus overwhich the subscriber has given his order.

Another object is to release the call receiving apparatus for use inreceiving an order pertaining to another call after the first order hasbeen received, and the manual switchingfunction performed by theoperator. In this Way I am. enabled to use a small number of callreceiving circuits common to 'a number of line circuits.

Another object of the'invention is to provide for a manual selection ofidle call extending circuits which. may be cord circuits,,

the selection being made bythe operator, and by the attaining of thisobject I cause the operator to be enabled to manually preselect the cal]extending or cord circuit which she can do prior to answeringthe call.and time is thereby saved.

Other objects of my invention and the invention itself will be moreclearly understood from adescription of the embodiment illustrated inthe drawings which are a part of this specification.

Serial No. 213,473.

shown in an extension of Fig. 1 on the sheet of drawing containing Fig.5.

F ig. 1 also shows a system of interconnecting intersection trunks forthe purpose of extending a call originatingon one of the lines to one ofaplurality of interconnecting trunk circuits shown in Fig. 3.

Fig". 1 also shows the means for extending what I term code wires fromthe impulse apparatus shown in Fig. 2 to code conductors 01" theinterconnecting trunk circuit, the particular code wires thus extendeddepending upon the particular line which is calling.

Fig. 2 illustrates a system of code interrupter wheels whereby currentimpulses or. in other words, circuit interruptions are caused to bemade, there, being a wheel for each number from. 1 to 10, and therebeing tour groups of the said wheels to denote thousands, hundreds,tens, units, and numerals or calling line numbers. Code wires extendfromthese interrupter wheels to the lines as illustrated in Fig. 1, onecode wire of each digit being associated with each telephone line. Amaster'impulse wire is also extended from. Fig. 2 to- Fig. 4 to mark thebeginning of a train of impulses and the end thereof, the same train ofimpulses being composed of consecutive series of interruptions from thedifferent orders of codewires.

Fig. 3 illustrates asystem of interconnecting intersecting trunkssimilar to that shown in Fig. 1, one of the sets of trunks beingextended from Fig. 1, and the other system of trunks capable of beinpconnected thereto under the control of the controlling apparatus alsoshown in Fig. 3 to call receiving trunks or circuits which are extendedto F ig. 4.

Fig. 4 shows the extension of the call receiving circuits from thedisclosure of 3 and operative apparatus individual thereto whereby anoperator may be connected to the call ,receiving circuit to receive acall. and to ascertain the number of the called line desired by theparty on the calling line.

Fig. 4 I nective apparatus associated with the call receiving circuitswhereby the said call receiving circuits may be connected to one ot aplurality of plug connecting circuits, two of which are also shown inthis figure. At the left of Fig. 4 are shown connecting plugs which areof the manually operated type, and which plug connecting circuitsterminate. On the right side of Fig. 4 is shown the automaticallyoperated apparatus associated with the said plugs, whose functions wilibe later described.

Fig. 5 shows electrically operated automatlo switches with circuitconductors and controlling apparatus for the said switches whereby linetalking conductors, such as the talking conductors 111 and 112 areextended thru contacts of the said switches to the terminals cc and Jr!of a telephone line having line comluctors and 1, and as shown in thedrawing of Fig. 5 having a substation A connected to the said lineconductors. In the drawii'ig of Fig. 5 showing this system, lia and 112represent the extended talking comluctors ot' the connected circuit Clshown in Fig. 4. 203 and 20% represent normally open contacts in theautomatically selected connecting circuit which are closed immediatelyfollowing the association of the said connecting circuit with the plugconnecting circuit of Fig. 4. 205 is the impulse relay' by means ofwhich the various numerical switches are set under the control ofactuating impulses received over the conductor 110 and thru theintervening contacts in its circuit produced by the contacts 13 ot' therelay 12 shown in Fi 1, as has been described; the said'impulses bymeans of the impulse relay 205 being transmitted to the stepping magnetsof the switches. Batteries of different potential are indicated in thedrawing of Fig.

Certain 0t these batteries which are indicated as being merely of twocells, may'be of 24 voltspotential, the other batteries indicated beingof 4 cells, may be of 48 volts potential. A selective system producingequivalent results to that shown in Fig. 5, and having a source ofcurrent oi but one potential may be employed instead of thatillustrated.

When this apparatus is taken for use by the manual selective act of anoperator, the apparatus is so arranged that current impulses will betransmitted over a private circuit conductor leading from the right ofFig. 4, and which is extended to Fig. 5 to operate selective switches ofan automatic selective system which may be any of the also illustrates aplurality of con-- common. types known to the art and which in theembodiment illustrated in this description is illustrated as being sucha system as that illustrated and described in the patent to A. E.Lundell, No. 1,19%851, granted August 15, 1916, whereby the apparatus ofFig. 4: controls the apparatus of Fig. 5 to connect to the talkingconductors which are extended from Fig. 1 thru the apparatus of Fig. 5the talking conductors of the calling line.

The current impulse apparatus ot'Fig. 4 is operated under the control ofthe code apparatus of Fig. 2, circuit conductors from which are extendedby means of the apparatus of Figs. 1, 2 and 8 to that of Fig. -l.

Referring now to the figures, Fig. 2 shows code impulse apparatus hereinillustrated composed of a series of interrupter wheels makinginterrupted contact with contact springs, these llltel'l'llptttl. wheelsbeing arranged in tour groups which 1 term units. tens, hundreds andthousands groups. In each group are ten interrupter wheels, each in acomplete rotation of the wheel carry ing shaft which may be common toall oi the wheels, but which shat't has been omitted in the drawing forthe sake of clearness, causing the contact springs to be opened from oneto ten times, depending upon the particular interrupter wheel.Preferably the interrupting segments of the wheels are so arranged thatnone of those of the second or tens set will be operated during the openative period of those of the first set, and the same true of the thirdand tourth sets; that is, each set will produce its contactinterruptions one atter the other, the thousands operating first, thehundreds second and tens third and the units last in order, there beingav time interval between the operation of each successive group.

(lode wires extended between the contact springs operated by a differentinterrupter wheel to apparatus associated with the subscribers linesshown in Figs. '1 and 5, and the current impulses produced by theinterrupter wheels are relayed thru apparatus of the subscribers linesbrought into action by the act of a subscriber making a call, to

u a conductor ot a call receiving circuit, such as illustrated in Fig.4, the combination ot code wires for each of the lines being ditt'erentfrom the combination of any other oi the lines. This arrangementprovides means whereby automatic apparatus brought; into action by theact of an operator in making connection with a called line by the use ofone of the connecting circuits of Fig. 1-, may while the said connectingcircuit is associated with the call receiving circuit conveying thecall, cause the. said current impulses produced by the code interrupterwheels of Fig.2 which interruptions are relayed to the apparatus of Fig.

4, caii'se the said apparatus to so control the automatic selectiveswitch mechanism of Fig. 5 to cause it to make a connection between theoperative terminals o't a calling line to the operative terminals of theplug connecting circuit whereby the plug connecting circuit finallyestablishes connection between calling and called lines, independent ofthe first established circuit from the calling to the call receivingcircuit; which first'established connection is merely for the purpose ofan instruction call circuit for the use of the operator in learning thewishes of the calling subscriber.

In the embodiment illustrated, I show apparatus to select the particularcall receiving circuit to be used for a given incoi'ning call, theselectin apparatus illustrated in Fig. 3 providing for the consecutiveselection .of call receiving circuits. These call receiving circuits maybe distributed among a plurality of operators and a sutlicient numberprovided sothat by the apparatus as se lected by all of them many of thefirst selected call receiving circuits will have been discharged fromuse by the connective act of operators, and again be conditioned toreceive new calls.

in this way-l obviate the necessity of coinpli ated interconnectiiigapparatus for these call receiving circuits to select busy or nonbusycall receiving circuits. and also by this means provide a very even,distribution of the calls throughout the entire switchboard.

ln order to reduce the number of such call receiving circuits necessary,I provide means under the control of an operator to limit-the time ofuse of each call receiving circuit, that is, the call receiving circuitis not required to be used for the periodoi --oi iversation betweenconnected subscribers stations, but only until such a time thesubscribers are connected together in conversational circuit, the callreceiving cir cuit then reverting to its idle condition, be-

ing dissociated from the connection circuit from which it is thereafterindependent during the period of the conversational connectionpreviously set up.

l also provide for each operators position a plurality otinterconnecting circuits, whereby an operator may manually select one ofthe said interconnecting circuits.

The selected interconnecting circuitvwill' thereupon under the controlof the identifying means above referred to thru the intervening callcircuit cause selective switches of an automatic selective switchingsystem to operate to connect'the calling line directly thru the saidswitches to the interconnecting circuit. The call receiving circuit isthereupon discharged from the connection and the subsequent operation orthe interconnecting circuit is very much like that of a cord circuit inthe ordinary manual telephone systein, the called-tor subscriber bemg,signaled and the supervising of the connection being taken care of bysignal lamps within the view of the operator, and the operator havingaccess to the connection by listening keys and capable of severing theconnection by disabling the connection switch of the interconnectingcircuit.

ll aving thus described my invention in its broadest aspects, I will nowdescribe the specific embodiment thereof illustrated in the drawingsaccompanying this specification, and will also describe the operation ofthe system from which other objects of my invention than those abovereferred to will be apparent.

Referring now to Fig. 1, at L and LL, 1 show central otlice apparatusindividual to two telephone lines extending from substations shown at AAfor the line LL, and at A in Fig. 5 for the line L. Circuit conductorsa, b, 0, (Z, extend from the line circuit 1.! to like referencedconductors of Fig. 5 in which figure multiple jacks J1 and 32 areprovided for the line L, and connector switch contacts cc, 1M and N) arelikewise provided for the line and shown in Fig. 5. the conductors c and(Z being the line talking conductors that lead from the apparatus ofFig. 1 to the substation apparatus at A on Fig. 5.

Assume now that the subscriber on the line L whose substation apparatusis shown at A, desires to make a call, he will do so by removing thetelephone receiver r from the hook closing the switchhook contacts a.and closing a circuit thercat to bridge the line conductors c and (Iwhich lead from that portion of the line circuit shown in Fig. 5

to the line apparatus of the line L shown in Fig. 1, and thrii normalcontacts 1 and 3 of the line cut-oft relay and the battery 't'eed tandemwindings 4 and 5 of the relay ti to the positive and negative poles ofthe central ollice source of current. from which source current willflow thru the said windover the said line to supply energizing currentfor the transmitter of thc substation A, and to operate the relay (3.The relay (3 will thereupon attract its :irmaturcs closing contacts 7.8, and 9 in circuits to be described. The contacts 8 and fl being closedtwo co-operating circuits will be thereby completed thru the windingsIt) and it olthe relay .12 which may be called the line impulse relay.which circuit includes the tour circuit conductors w, ii and H1. 'l hcsesymbols relate to the units. tcns. hundreds and thousands digits ol thenumber characterizing the subscribcrs line L with which the thci'cbyreferenced circuit conductors are associated. Similar circuit conductorsto u, 2. l1 and f/L- for the line I; are pro vided for all of the linesof the system being Ill) described, the conductors no, it, hit andfit-Ht designating like conductors tor the line LL.

This description will be confined to the operation of" the systemwherein the line L is the calling line. and the line LL is the calledline 01 a circuit connection to be established, and the establishment ofwhich connection is described.

At the lower part of the sheet of Fig. 1 are shown four groups ofcircuit conductors,

there being ten circuit conductors in each group. These circuitconductors I term code wires, the first group oi code wires being forthe purpose of providing the units design-Ln tion of any telephone line,the second group being provided to designate the tens digit of atelephone line, the third group the hundreds digit and the fourth groupthe thousands digit thereof. These code wires are shown extended fromFig. 1 to Fig. 2, and on Fig. 2 are shown the code interrupting wheelsfor each of the circuit conductors of the four groups. Other circuitinterrupting mechanism than that specifically shown in Fig. 2 may beassociated to perform the functions required of the specific structureshown in Fig. 2. In the embodiment illustrated the code impulse wheelsare assumed to rotate synchronously as on a common rotating shafttogether with a master impulse wheel w shown to the left of the fourgroups of impulse wheels in Fig. 2. The bottom row of impulse wheelsshown in Fig. 2 are connected in electrical circuit with the ten codewires of the group Tl'i, each conductor of the ten in the group beingconnected to a different impulse wheel; the bottom conductor of thegroup shown in Fig. 2 leading to an impulse wheel TH.1, and the top codewire oi the thousands group leading to the impulse wheel TH-10, thefirst named impulse wheel having a single short circuit interruptinginsulating piece in the periphery of the conducting segment thereof, andthe last named impulse wheel having ten short circuit interruptinginsulating pieces in the periphery of its circuit conducting segment;the other intermediate code wires being connected to impulse wheelshaving ditierent numbers of insulating circuit interrupting pieces. fromtwo to nine pieces in the various wheels, these insulating pieces beingso arranged as shown in the drawing in what may be called the firstquadrant of the wheel circumferences. The conducting segments of all thewheels of this first named group are connected to the negative pole ofthe central .oilice source current, and the hundreds next above thethousands group of wheels like insulating pieces are arranged in thecircuit conducting segments, only they are placed on what may be termedthe second quadrant oi the wheel.

It will be noted that between the first and second quadrants in eachgroup of wheels above mentioned, there is a circuit conducting space onthe periphery of the wheels considerably broader than the circuitconducting spaces between the insulating pieces. The two other groups ofthe wheels for the tens and units designations are like the wheels ofthe thousands and hundreds'desig nations just described, only thecircuit conducting portions and the insulating pieces are arranged just180 degrees away from the like portions of the before described wheels.In this way four wheels for like digits in the different groups willproduce a like number of circuit interruptions, only the circuitinterruptions will not occur simultaneously, being produced in regularorder one after the other as the four circuit interrupting quadrantscome successively under the brushes attached to the code wires which areall arranged in the embodiment illustrated to contact .on the same sideof the wheels. The circuit conducting segment of the thousands as hasbeen described, is connected to the negative pole of battery, thehundreds group to the positive pole of bat tery, the tens group to thenegative pole of battery, and the units group to the positive pole ofbattery.

The impulse relay 12 oi Fig. 1, has its windings 10 and 11 placed inseries with the units and hundreds, the tens and hundreds code wires,respectively, by the operation of the relay 6 closing contacts 8 and 9as before described and each wheel of the two pairs producing currentimpulses of dilierent polarity. It is apparent that current impulseswill. be produced in the circuits described, thru the said windings 10and 11, producing sets of magnetic impulses one after the other in thecore of the said relay, so that the contacts 13 thereof will be vibratedto produce successive trains of current impulses characterizing the fourdigits comprising the number of the calling telephone line. The shortcontact piece of the wheel which is con nected to the ground pole ofbattery as will be later more fully described producing a single impulseof current over its connected conducting wire after the associatedcircuits as will be later described are properly conditioned, the timingof this single current impulse being such that it will occur just beforethe thousands train of circuit interruptions begin. The circuitconductor leading from this master impulse wheel leads to theinterconnecting circuit mechanism of Fig. 4: which will be laterdescribed.

When the relay 6 was operated contacts 7 were also closed completing acircuit from the negative pole of battery, thru the resistances 14 and15 to the ground pole of battery, and thereby raising the electricalpotential of the circuitv conductor 16 leading thru the winding 17 ofthe line eut-ofi relay C of the line and the circuit conductor a leadingto like referenced circuit conductor a of Fig. 5 tothe thimbles ot' themultiple jacks kll and J2 of the calling line. This raises theelectrical potential of the said multiple jack thimbles and conditionsthe line to'test busy when the ordinary manual busy test is inade bytouching the plug oi interconnecting circuit to the said thimbles in theusual manner. A branch circuit is also closed by the contacts 7, thecircuit being' traced thru the said contacts and a winding 18 of aconnection relay l9. and thru normal contacts 20 ot a relay 21 to theground pole of battery.

The object ol the completion of the circuit just traced is tointerconnect circuit conductors c. (7 and fot the calling line to anintersecting trunk circuit. such as the trunk circuit B or the trunkcircuit l). the trunk B in the description being taken as the seizedtrunk circuit. but if the trunk circuit 13 is busy, that is. taken foruse by another line such as the line LL. the relay 21 would have beenoperated. and the contacts 20 opened so that the circu t just tracedint-hiding a winding 15s of the relay 1!) would not have been completed.but instead a circuit would have been completed con'iprising a winding18 I) of a rclay 1'!) l). the circuit being es tablished thru contacts20 I) of a relay 21 i). all associated with the trunk l). and havingparts which correspond to parts referred to for the trunk l3. llikcwiseit the trunks B and l) were busy the next succeeding trunk would heseized for use upon the initiation of the call by the subscriber at A asdo.- scribcd. The circuit just traced hcing completcd. current will flowover the same from the source ol current included in the circuit thruthe winding 18 oi the relay 1!) and then will cause this rclayto beenergized thereby attracting its armatures and closing contacts 22. 23.24 and 25.

The contacts 22 being closed a holding circuit is thereby establishedfor the relay 19, including its winding 20. the circuit being traced asfollows: From the negative polc till ol the source of current. the nowclosed contacts T of the relay L. the winding 26 of the relay 1 the nowclosed contacts 22 thcrcol. the winding of the relay 21 which isindividual to thc trunk circuit and connnon to the group of linescapable of being connectcd to the trunk: the circuitlu-ing thereaftertraced thru conductor it which leads to a like rctcrcnced conductor R onFig. 3. where the cir-uit of the trunk line may be seen extended. andthru the winding ol' the relay 27 to [he-ground pole ol the source olcurrent. This will cause the operation ol the relay .l to open contactsE l. whereby another line may not be connected to the trunk linc l andwill causc the contacts 2 to be closed extending the circuit of theconnect ing ground or the trunk seizing circuit, to contacts of a likerelay for the trunk circuit 1) which is assumed to be the nextsucceeding trunk circuit capable of being seized for use by a callingline. The relay2? will also be operated in series with the relay 21, andwill attract its armatures closing contacts 2!) and 30. The contacts 29being closed, a circuit will be completed including the said contactstraced as follows: From the negative pole of the source of current thruthe said contactsQf) and winding 31 of the relay 32. contacts 33 ot' arelay 34, a brush 35, a contacting segment 36 of a rotary switch SW".and thence thru the winding of a relay 3? to the ground pole of battery.This circuit being closed. current will flow over the same operating therelay 37. which being of very high resistance will so limit the strengthof current flow that the serially included winding 31 of the relay 32which is of relatively low resistance will not energize the relay 32sufficiently to operate its contacts. The relay 32 and a like relay i352tor the trunk line I) are arranged to interconnect a call receivingcircuit M to the associated trunk line B or D.

In this description. although but two trunk lines of arch tvpe areshown. it IS understood that other trunk lines might be employed inpractice to increase the volume of service. as may be required of thetrunks.

The relay 34 is individual to the call receiving trunk line circuit Mand is common to all of the trunk lines B and D which may have access tothe ,.trunk M. The switch SW and the associated magnets 37 and 38together with associated apparatus is common to 'all of the callreceiving trunk lines. such as M and N shown in the drawingof Fig. 3.and, operated to condition a next succeeding call receiving circuit tora subsequent call upon establishment of a pre ceding call connectionwhereby an incoming trunk line. such as B or D is connected to a callcircuit. I

it is understood that other forms of interconnecting switch mechanismmay be employcd to produce the intcr-connection of the trunk lines ofthe various types. such as rotary switches or cross-bar switches. as area part of the art.

The relay 3? having been operated. the contacts 89 thereof will beclosed completing a. circuit including the source of current. and theslow releasing magnet 38 which is the inolor magnet for the switch SV.the switch bill' beingvol' the hack stroke type. being propelledlrom'onc operative position to another upon the dc-cncrgization of theslow releasing magnet 38. which may be made slow releasing in anysuitable way. The magnet 38 being operated. the armature lhcrcol will bcattra ted and will cause the carried pawl to fall into the nextsucceeding notch of the ratchet wheel RW. So that upon thede-energization of the magnet 38 which now takes place.the ratchet wheelRW will he propelled hy the action of the spring 40 to its next positionof rest causing the next operative position of the switch SYV. -Themagnet 38 heing energized. contacts 451 will he closed upon a tullattraction of the armature short circuiting the high resistance relay37. This will produce a slow releasing 01' the armature oi the relay 3?and of the slow release relay 38. hut in the meantime will accomplishthe operation ot the relay 32 hy increasing the flow of current from itswinding 31 in the circuit which has heen described.

The relay haying heen operated, a locking circuit will he completedtherefore including contacts #2 and a winding 43 thereof. and windingsot' the relays 3 t and 44 ot the :all receiving circuit. the relay ll.heing shown in Fig. -l. This locking circuit is traced as follows: Fromthe negative pole of the source of current. thru the contacts 30 ot therelay 27. the contacts 42 and the winding 42-3 of the relay 2%). thewind ing'ot the relay IE4. circuit conductor lto which is shown in Fig.i. and the winding of the relay 44 to the ground pole of the source ofcurrent. (urrent from the said source will tlow over the said circuit.causing the relay 3'2 to remain operative and cans-- ing the operationot the controlling relay 3i. and the relay l-l ol the call receivingcircuit. The relay ftl heing operated. contacts 33 thereo't' will l)(*0l)tlltll to open the circuit leading to the relay 3i. and also to openthe common circuit ot the trunk seizing windings'as I31 and as 131 oi'such another trunk connecting relay as 3:! and 132. so that the callcircuit cannot he taken tor use hy another incoming call of anothertrunk. The relay it heing operated will close its contacts 45 and it).the contacts 46 completing a circuit for the answering signal lamp 4?thru normal contacts 43 ot a relay 49. this circuit including the sourceof current. and

the lamp i? will he operated to apprise the operator that a call existson the call receiving circuit M. with which the lamp 4? is associated.

Another call receiving circuit is shown at X in Fig. 4 for the sameoperatoi"s position. ()ther call receiving circuits. such as N shown inFig, ll. lead to call answering apparatus on other operators positions.The call circuits M. N and others not fully shown in Fig. 3. hut whichit is understood may hev included in the system of my invention lead toother operators positions. the preferred order in which these callreceiving circuits are allotted for the use of succeeding incoming callshy the call allotting switch SW, being such that the first callreceiving circuit of the first operator will first receive in order toeach position. until calls have been allotted. to all call receivingcircuits. which preterahly may he tive in number for certain conditionsin telephone traliic which are ohtainalile in practice. whereupon thecall allottingswitch hWVwill again allot a call .to the first -allcircuit of the first operator and so on. itbeing proposed to thusdistrihute the calls inahsolute rotation as to call circuits and as tooperators position.

The line talking conductors c and (Z of the calling line have now beenextended by means ot contacts 23 and'Ql of the relay 19 ot Fig. l. andhy contacts 50 and 51 of the relay 32 of Fig. 3 to the listening keysprings 52 and .33 of the listening key 54 of Fig. 4. cilll on the callreceiv ng circuit M. by operating the listeningkey 5% and closing thecontacts thereot to connect her operators telephone set shown at O. tothe talking conductors ot the telephone line extended as dcsci'ihed. Theoperator conversing with the suhscriher will learn the number of thecalled-tor line. in the operation of the listening key contacts 55 wereclosed completing a circuit for the relay 49, the said circu't includingthe source of current. the winding ot the said relay. said contacts andcontacts +3 ot the operated relay 44. This will cause the relay 49 to beoperated. \\'l\l(ll immediately closes the locking cir cuit for itselfincluding its winding and its contacts no. independent of the contactsoi the l'stening key. The listening key may now he opened. the relay 49remaining operated thru its locking contacts. The signal lamp 47 isextinguished and a signal lamp 5T will he lighted in its place toindicate that the call on the call receiving circuit M has heenanswered. hut the desired eonnect on not yet completed.

The circuit for the lamp 5? includes now closed contacts 58 ot the relay49 and normal contacts 55) ot the relay (30. and contacts 46 ot' therelay 44 together with circuit condllctols leading thru the saidcontacts. and including the source of current. The operator hayinglearned the numher of the ialled-t'or line. will now complete theconnection hy means of one of a plurality ot connection switches underher control and which are herein illustrated as heing plug andjack;manually operated switches. The operator may use any conuectingplugol' the group provided for the purpose. and time is The operator may nowanswer thesince an operator upon completing one contil) nection bymanipulating one connection plug, may immediately manually preselect theplug for the next connection by picking up such a plug as she desires touse for the next connection.

In the illustrated 'form of my invention I arrange multiple jacks of thecalled lilies on, the operators position in proximity to the said plugwhereby the operator may by inserting the plug into the said multiplejacks make connection with called lines. Such an act will cause anassociation of the call re.- ceiving circuit last attended and theparticular plug circuit manually selected. This is not a permanentassociation as will be seen from the further description.

To continue'the'narrative. the operator having manually selected an idleplug circuit will make the busy test in the usual way by touching thetip of the connecting plug. such as the connecting plug P1, to thethimble ot' the called line jack which we will assume is the jack J3 forthe called line l-dl shown in Fig. 1. it the called line is busy, thebusy condition of the toe will he indicated to the operator by theexistence of a raised potential of the jack thimble ot' the jackuli'lwith reference to the potential of the ground pole of the exchangesource oi current. This is accomplished by the means shown and describedtor the line L consist ing ot'the contacts 7 of the relay ii. theresistance coil 14. and the winding 1T oi the relay which provided acircuit from the negative source of current to the thimbles ot the linejacks J1 and J2: or it may be done by a connecting plug being previouslyplaced in one of the multiple jacks of the line. such as the jack J4.whereby the shank oi the plug to which is connected a circuit leading tothe negative pole of battery makes contact with the said thimble to rase.

the potential thereof. it the line-is busy. current from the saidnegative pole of the source ot current will when the busy test is made.traverse the tip of the talking strand 61 of the ctumccting'circuit (Pthru normal contacts (39 of the relay (iii and normal contacts Slot therelay 5 to the common test relay tor the operators position 66. and thruthe said relay to the ground pole of the source oi" current energizingthe sa d relay. causing it to close its contacts (ii' and ihcrcbyestablishing a circuit for the flow oi current from the source ofcurrent including an inductive winding lib on the operator's in ductioncoil inductively related to the opcrators rece ver 1'39. which willthereby be operated giving the charzu'teristic busy click. The operatorwill thereupon tell the subscribcr that the line desired is busy. Thesubscriber by restoring his receiver lo the book will open the contactsol' the hookswitch. releasing line relay ll which by its con actsoperated the relays wh ch have been described as having been operated inthe establishing of this connection to. the present point ofdescription. and these relays will therefore be released restoring theapparatus to normal. If. however. the operator does not in making theusual busy test tind the line busy. she will insert the plug PI for theconnecting circuit (1* into the jack J3 ot the called line makingconnection thereby with a pair of talking conductors ot the line and alocal private wire of the line circuit to like talking conductors and aprivate wire of the connecting c rcuit (71 l\ circuit will thereupon beclosed including a winding Tl) of the cut-oti' relay Tl oi the calledlin and the winding of the relay (3.") for the connecting circuit thesaid circuit including the source of current. and current trom-thc saidsource will flow over the said circuit energizing these relays whichwill attract their armatures.

The contacts T2 and 73 ot' the relay Tl of the line circuit will beopened to remove the normal association between the call initiatingapparatus of the line circuit and the line circuit proper. The contacts7% ot' the re lay T]. will be closed placing the winding 75 ot' therelay Tl in inu'ltiple'with the winding Tl). The relay 65 ot' theconnecting circuit (1* shown in Fig. 4 being operated will close itscontacts iii. 7?. T8 and T9 and open its contacts (34. The opening ofthe contacts 64 will dissociate the busy test relay (36 from theconnecting circuit. contact To will complete the connection of the tipsnpervisorvrelay winding to the talking strand 81 ot' the connectingcircuit. The closing of the contact T? will complete a circuit includingthe source of current and normal contacts 82 ot the relay S3 tor thesupervi ory lamp R l lighting the said supervisory lamp. The closing ofthe contacts 79 will complete a circuit to associate the conneciingcircuit (l temporarily with the incoming call circuit M. the said est:blishing circuit including the said contact 79 ot' the relay (3."). thecontacts H5 ot' the relay St). the winding H? of the relay S normalcontacts H9 oi the relay (it and now closed contact 91 ot' the relayill. and the source of current which being in said circuit will cause acurrent flmvovcr lhe same energizing the relay b5. lhis relay W4 is acalied circuit interconnecting relay. and will close its contacts J3 andill. The contacts 94" being closed a holding ircuit tor the relay RHwill be conr pletcd. the said holding circuit including the source ofcurrent. the winding of the relay Hliol' the connecting circuit and winding 95 of the relay t. the winding of the relay ll) of the called ciruit. and now closed contacts lti ol' thc rclay H ol' the called (incuit. The establishing ol' this holding cir cuit including the windingsof ihe relays li and HG cau es by the breaking of the con- The closin otthe &

included in a circuit with the source of current and now closed contacts97 of the relay ($0. This lamp 96 will remain lighted during the fullperiod in which the talking conductors oi the connecting circuit areextended by the operation of automatic selective apparatus to makeconnection with the talking conductors of the calling line as will bedescribed.

The contacts 98 of the relay 86 are now closed completing a circuit fromthe common master impulse wheel shown in Fig. 2 and indicated at w. thecircuit being only completed at such intervals as occur when the shortsegment 99 makes contact with the brush 100 to mark the intervalsbetween successive trains of code impulses denoting calling line numberdesignations. As soon as the contacts 99-100 of the rotating impulsewheel make contact. a circuit is Completed from the ground pole ofbattery, thru the said segment and brush of the impulse wheel, circuitconductor ww leading from Fig. 2 and extended in Fig. 4, the saidcircuit being completed thru contacts 98 of the relay 80, normalcontacts 101 of the relay 102, the winding of the relay 103 to thenegative pole of thesource of current thru contacts 78 of the relay 65.Current flowing over this circuit will operate the relay 103. This relaybeing operated will close its contacts 101.

\Vhen the line conductors c and d 01 the calling line were extended bymeans of contacts 23 and 24 of relay 19 of Fig. 1. and by contacts 50and 51 ot' the relay 32 of Fig. 3 to the listening key springs 52 and,53 of the listening key 54 oi Fig. 4, as has been previously described.a circuit was also completed to extend in like manner the circuitconductor which I call the impulse wire from the ii'itermittentlyoperated contacts 13 oi the relay 12 of the calling line circuit thrucontacts 25 of the relay 19, thru' contacts 105 of the relay 32 to theconductor 106 of Fig. 4. and which conductor 106 is later furtherextended by the closing of contacts 93 of the relay 88 upon theinsertion of the plug ll into the jack of the calling line; theextension being made thereby to the conductor 107 leading thru normallyclosed contacts 108 of the relay 109 shown in Fig. 4, and now thru thecontacts 104 of the relay 103, the said contacts having been closed asdescribed by the operation of the relay 103. and over circuit conductor110 of Fig. 5, and thru the winding of the stepping relay 205 to thenegative pole of a source of current shown in Fig.

The series of interruptions produced by the contacts 13 of the relay 12shown in Fig. 1, will now cause the stepping relay 205 to retract itsarmature opening the circuit for relay 215which in turn retracts itsarmature. Relay 216 being slow to release remains up throughout theseries of impulses. With each deenergization of the relay 215, a circuitis completed from the 18 volt battery through the primary steppingmagnet 217 and the escape relay 218 in parallel. and thence through tiefront contact and armature of relay 216 and the back contact andarmature of relay 215 to ground. Magnet 217 and relay 218 will both beenergized, and relay 218 will close a circuit from battery through theleft winding of the escape magnet 211, armature and contact of relay218, wiper 219 and the right winding of magnet 214 back to battery, thusenergizing the es cape magnet. The side switch, however, will not beoperated this time until the escape magnet is deenergized. Relay 218being slow to release is held up during the series of impulses. Magnet217 rapidly attracts and retracts its armature, moving the brushes 209,210 and 211 01 the selector switch from group to group of the trunkterminals.

Upon the termination of the series of inipulses. relay 205 will remainenergized, and will hold the circuit for relay 215 closed. Relay 218will then retract its armature, opening the circuit for the escapemagnet 21 1 and causing the side switch to moveto position 3. As theside switch moves to position 3 the circuit for relay 215 isinterrupted, and it retracts its armature. but a. substitute circuit iscompleted for the hold ing relay 216 through the side switch wiper 213in position 3, thus preventing the release of the switch.

The escape magnet 214 is-employed as a test relay. in position 301 theside switch, a circuit is closed from the. 24. volt battery throughresistance 220. wiper 219 and the right winding of relay 214 to ground.The current flowing over this circuit, is however. insullicient to causemagnet 214 to pull up its armature. At this time a circuit is closedfrom battery through the left winding of magnet 214 and wiper 221 to thetest brush 209 of the selector switch. The test or guarding contacts oftrunks leading to idle sclcctor switches will be connected to groundthrough a side switch wiper as 13 at the second selector and the leftwinding olthe cscapc magnet 214' of that switch. It. however. a trunkleading to such switch is busy, its test or guarding contact will beprovided with battery potential. This may be supplied inseveraldift'erent manners, depending on the stage of operation ot the switchwhich has selected the connecting circuit. and of the switch at whichthe circuit terminates. it the connecting circuit has just been selectedat one ot its multiples and the side switch ot' this connecting circuithas moved to position 2. it is obvious that the test conthcts will, beconnected to the 45% volt battery througlrwiper l3 and stepping relay215. At this time. however. the it volt bat tery at the impulse relay20;: will also be connected to said test contact by a circuit extendingthrough wipers 213 and 221.. in position 4-. 'llherel'ore. the potentialof the test contact will be of substantially Q-l volts, the current;will theret ore not tlow through the left winding of magnet 2141 in sucha manner as to cause itsenergiaation. l t the impulse wheel connected tothe connecting circuit is at. this time transmitting ii'npnlses, thebattery at the impulse relay 205 will he removed from the multiple testcontacts of the connecting circuit with each. deenergization of relay9.05. leaving only the 4-8 volt battery at relay 21;) associated withsaid contacts. The flow o'l' current. however. trom this batterv throu'h the left windin ofmagnet 21 i. is in a direction to oppose the flowof current through its right winding, and magnet. 2141 will not beenergized. It the side switch wiper ot the s .vitch at which theconnecting circuit terminates is in posi tion 3 or position l. the samecondition will exist except that the test contact. will be connected tothe volt ljiattery through relay 216' instead oi through relay 2153.switch associated with a multiple t the connecting circuit is just inthe process oi testing and the side switch has not yet moved to positiont. the second switch to arrive on the .multiple test contact will findbattery potential thereon and its test relay or magnet 214 will not beenergized. Vlhen the second selectorside switch was moved to position 3.a circuit was established from battery through the secondary steppingmagnet 222, wiper 223 and interrupter 22 to ground. This cirouit will bemaintained and the brushes 209, 210 and 213 will be stepped from trunkto trunk until the contacts of an idle trunk 'are engaged, when currentwill flow through the left winding of magnet 21th] a direction to assistthe current flowing through its right.

win .ling, thus energizing the escape magnet and moving the side switchto position 4.

It is obviousdrom the preceding description in what manner succeedingselector switcae's would be operated. The secondary magnet of theconnector switch might be arranged to be substituted by a side switchwiper tor the primary magnet in the circuit controlled by relay 215. Itis believed this is obvious and will not require further description.

it the By means of the apparatus of Fig. l l)()\\'l1 and described orotherwise indicated, the talking conductors 111 and 112 of the ounectiugcircuit ot' Fig. l are extended to the calling line having a substationA,-t his circuit beingindependent ot the circuit previously had whichmay be called an instruction circuit tor the operator from the Saidline. conversational circuit is now C0111- plete includin; the saidconductors and contacts ot the switches ot the system of Fig. 5 from thecallingsubscriber's line to the called subscriber's line thru thetalking conductors ill and 112 of the connecting circuit ot Fig. l andcontacts (52 and fill of the relay 33 of the said connecting circuit.and thru co-operating contacts of the plug and jack switch ll-.l8 bymeans of which as has been described. connection is made with the calledline .llli shown in Fig. l. The ringing of the called substation may nowproceed in the usual manner for manually ofae 'ated systems.

The circuit of the impulse conductor 110 of Figs. l and 5. is controlledby contacts 108 of the relay 105}. and these contacts re maining closedduring successive sets of im-, pulses until a series of selectorswitches of Fig. 5 are opuated as described, to make ("Ulljltt'tlullwith the calling line. The conversational circuit established thru theconductors and contacts of theswitches ot the system of Fig. 5 of the'alling subscribers line to the plug connecting circuit CP of Fig. l. isnow operative to cause the opera-' tion of the bridged subscribersbattery feed relay 231. which is now included in circuit with thesubscrihens line thru the said con tacts. the circuit including thesubscribers instrument and the central oflice source of current.T-hci-elay 231 will thereupon attract its arniatures upon the flow ofcurrent thru the said circuit and from the said source contacts 232 and233 being closed. The contacts 232 being closed .a circuit will becompleted including the said contacts. a winding ot the relay 10$) andnow closed contacts 78 ot the relay .35. together with the source ofcurrent. Current from the said source wilbtlow over the slid circuitoperating the relay 105). which will attract its armatures closing thecontacts 236 and 237. and opening the contacts 108, the me chanicalarrangement being such that the contacts 237 are closed before thecontacts 108 are opened. This in. order to maintain the/circuit ofconductor 110 controlling the selective switch systeu'i oi l ig. closed.even though the original circuit for the said switches thru the contacts108 are opened, the circuit being maintained closed thru. the contacts237 and the winding of a relay 238 to the ground pole of battery. The relay 238 being included in this circuit, current will flow thru itsWinding and out til over the conductor 110, and the relay will beoperated. and the relay 200 or Fig. will be maintained operated to holdthe established connection. The relay 238 being; operated will closecontact-23.) in the circuit of the calling snbscribers signal 230 whichwill not at this time be operated, because of the open contacts 23% ofthe relay 219;. the said contacts being in its circuit.

The relay 109 being operated. as descrihed. a holding circuit isestablished therefor including contacts 236 closed by its operation andnow closed contacts 78 ot' the relay 65, the said holding circuitincluding a winding 2&1 of the relay 109.

The selective system of Fig. 5 having established connection with thecontacts of the calling line, a circuit is completed for a winding ofthe cut-off relay of the calling line including contacts 7)?) of the.connector switch, circuit conductor Z) of the line circuit leading thrua winding 242 of the cut-0t: relay C of the line circuit. the saidcircuit including the central oliice sourcc of current, contacts of theselector switch system oi Fig. 5 and the central olhce source ofcurrent. The cut-oil" relay t will thereupon be ope 'ated, opening its"contacts 1 and in the circuit of the line rclay 8 to deenergizde thesaid line relay. and the contacts 2 will be closed to connect thecircuit conductors u. and l) of the line together, so that the increasedpotential of the conductor 7) loe duplicated on the condoctor a in orderto make the test contacts or and 1/ of the multiple jack of the saidcalling line test busy to prevent the intrusion of another operatorsconnecting circuit. The line relay 6 of the line being deeitei gized. itwill open its contacts 7, 8 and 9 an restore the relay 12 of the linecircuit, and

the relays l9 and 21 of Fig. 1, and 27, 32 and 34 of Fig. 3, togetherwith relays 44, ell), 60

and 88 of Fig. 4; these relays being involyed in the connecting systemfor the instruction circuit which has been described. and in turnsuccessively control ing various p0rtions of the instruction circuit.each of the relays bein controlled by preceding relays in theinstruction circuit, and the contacts ot the controlling line relay 6being opened, these relays will be all restored to normal as will beapparent from the torcgoing description, allowing the instructioncircuit connecting links involved in the established instruction circuitconnection to revert to the use of a subsequent incoming call.

The ringing of the called substation is initiated by the (lepressal ofone of the keys K K 3 or K, depending upon which station of a partyline, 'it the called line is a party line, it is desired to signal, andthe contacts 240 which are mechanically associated with all of theringing keys will be momentarily closed during the demessal of any ofthe ringing keys. these ringing keys being mechanically locked inringing position. The ringing relay 0:: is operated and the ringingproceeds. The circuit for the ringing relay (53 includes its winding andthe contacts 240, together with normal contacts 24-h of the relay HI;and now closed contacts 233 of the relay 231. resistance coil 242 andnow closed contacts T!) of the relay (35 togctlier with the centralollicc source of current. Upon the operation of the relay ($3, thecontacts 243 thereof arc closed. hridging the contacts 240 of theringing key to arise the locking circuit for the relay (53 independentof the said kcy contacts.

The contacts 24% and 2 of the relay (53 are now opened, opening thetalking conductors leading to the plug Pl which is understood to be nowinserted into the jack J3, and the contacts 245 and 240 leading from thekey selected ringing generator,

such as the generator (ll, and the serially iuclulled central source ofcurrent as Bl. tlurrent l'roin the said ringing generator will flow thluthe said ringing contacts 2l5 and 24-6 thru the talking conductors G1and 247'leading to the. called plug, and from I thence thru the contactsof the plug and ack switch P1 and J3 and over the line conductors 24Rand 249 of the called line, and thru the windings oi the calledsubscribers telephone bell 250. ringing the said telephone bell. Thecalled subscriber answcring his telephone will remove his receiver fromthe hook, closing contacts 25L bridging his telephone transmitter acrossthe telephone line, and current from the central source of current B1flowing over the circuit for direct current thus established willoperate the trip relay 2:32 in the plug connecting circuit C1" of Fig.at, causing it to close, its contacts 253 to bridge the said contactsacross the winding of the ringing relay (33 to dcenergize the said relayandcause it to restore its armatures to normal, opening the ringingcontacts 24-5 and 246 and the locking contacts 243. and closing thetalking contacts (32 and 244. These last pained contacts being closed, acircuit is complete from the subscribefs substation apparatus thru thesaid contacts, and thru windings 80 and 290 0]" the bridged subscribefisbattery teed relay S3 and the central oliice source of current. Currentfrom the said source operating the said relay, will cause the contacts241 in the circuit of the ringing relay (33 to be opened to prevent thereenergization of the said relay. and the contacts 82 to extinguish thesignal lamp 8%. tional circuit and will so continue until the end of theconversational period, whereupon they will restore their receivers to'their hooks, opening their respective line The subscribers are now inconversacircuits. The openingot the called subscriber's line circuit andof the calling subthe-cut-ofi' relay T1 of the called line to its normalcondition and restoring' the relay in the. plug: connecting circuit toits normal dcenergized condition. The relay (5?) being restored. circuitcontrolling contacts Tt'. T7. T8 and 7!) thereof, will be opened torelease the apparatus of plug connecting circuit (l the contacts 78being operative to release the relay 103 which thereupon opens itscontacts 104 in the circuit of'the conductru 110 leading to the relay205 shown in Fig. 5, the said relay 205 being thereupon restored tonormal. The contacts of the relay 205 being opened, the apparatus of theselective switchsystem of Fig. 5 which is'beof these contacts, will berestored to normal upon the opening thereof. and the switch involved inthe established connection as has been described, will be restored tonormal position.

I have described a specific embodiment otv .mymventmn for the sake ofconveying and understanding of the same, but i am a "are that numerousand extensive departures may be made from the embodiment describedwithout departing from the spirit of the invention.

.Vhat I claim is my invention and wish to cover by. U. Letters Patent is'1. In a telephone system. the co1nbination with an operators:instruction circuit for calling telephone lines, of a signaling circuitfor the said instruction circuit, the said signaling circuit being underthe .control of subscribers ljne apparatus,v of an operatofisconnecting-circuit, and manually operated means to cause the saidinstruc tion circuit to be associated with the said connecting; circuit,apparatus in the said connecting circuit operating under the control ofthe said signaling circuit to establish j a conversational. circuit withthe calling line, and manually operated means to cause the saidconnecting circuit to be connected with a called line.

f 2. In' a telephone system. the 'combination'with telephone lines, ofcall receiving apparatus therefor, call means for connecting a callingline to an idle call receiving apparatus, aplurality of manuallyoperated connection switches normally dissociated from said callreceiving apparatus,

said connection switches being manually selectable for use. and meansresponsive to the selection o'l' said connection switches to intei conmct apparatus associated with said connection switches and a callreceiving circuit in which an answered call resides. and governing meanscontrolled thru the said connection to extend a connectiontroin'thomanually selected switch terminalsto teriuinals ot the callingline. and means automatically responsive to the extension ol 'the saidconnection. to. isolate said call receiving circuit from the saidcalling and called lines and connection switch apparatus.

3. In a telephone system. the combination with a plurality of telephonelines. a plurality oi call receiving circuits therefor. interlncdiatecall distributing meansv whereby a calling line is connectedto an idle receivin; circuit. an operators key to associate an operatorstelephone set with a call receivmg circuitto which a callingline isconnected. a plurality of connecting circuits manually selectable foruse in connecting:

calling and called telephone lines'norn'ially dissociated from said callreceiving circuits.

and means operative upon a given connectmg held operative bv thecontinued closure in; circuitbeing taken for use by an amator and underthe control of a connection switch connected to a called line. totemporarily associate apparatus in the said cou-- the said connectingcircuit apparatus is caused to extend aconversational circuit fromthe'connected called telephoneline to a callin telephone line, the saidextended connection beingindependent of the pr .viously establishedconnection to the said call receiving, circuit, and means operablethereafter to dissociate the said connecting circuit and the said callreceiving circuit.

4t. In a call distributingsystem, a combination with an operatorsinstruction circuit. of a calling telephone line connected nectincircuit with the said call reeeiviicn lltl thereto, a selectiveswitching system and'a connection ,switch individual thereto and underthe control of an operator to make connection between the said selectiveswitch system and a called line, the said selective switch system beingtemporarily under the control of apparatus individual to thecalling lineand extended over the said instruction circuit to the selective switchsystem,.

and means operable upon a connection being established between callingand called. lines over the said selective switch system; whereby thecontrol over the said selective switch system by apparatus of the saidline and instruction circuit is dissociated.

In a telephone system, telephone call indicating means, means to operatethe said indicating means. an operator's set. a calling telephone linecontrolling the said indicating means, means to cause the said telephoneoperators set to be connected to an extension call circuit of thecalling telephone line. manually operated switching apparatus.automatically actuated apparatus operating under the joint control oi:the said manually operated switching apparatus and said calling lineapparatus to cause a separate conversational circuit to be establishedbetween the calling telephone line and an operators connection circuitwhereby the operator may establish a connection between calling andcalled telephone lines independent ot the initial call circuitapparatus.

(3. In a telephone system. the combination with a main exchangeswitchboard and a plurality of substation telephones, telephone linesleading from the said substations to the main exchange, a plurality ofoperators positions at the main exchange, a pin ality of operatorsinstruction circuits for each opcrators position, call distributingcircuits and apparatus to interconnect a calling subscribers linecircuit with an idle one of said instruction circuits whereby anoperator may be instructed concerning a desired connection by thesubscriber on the said calling line, a plurality of link circuits at thesaid operators position, each of which is adapted to be manuallyselected for use by the operator", an automatic selective switch systemunder the control of ap paratus in each of the said link circuits,connection switches to interconnect called telephone lines with the saidlink circuits, the said connection switches being operator controlledand apparatus in the said link circuit operable upon a connection beingmade between the said link circuit anda called telephone line'toassociate the said selective switch system and a selective switchcontrolling conductor of the said instruction circuit, to control theoperation of the said selective switches, means to cause the saidswitches to operate to connect the said link circuit talking conductorwith the talking conductors of the calling telephone line whereby thecalling and called telephone lines are placed in conversational circuit,and means to isolate the call distributing and operators instructioncircuit from the connection.

7. In a telephone system, the combination with a plurality of telephonelines, of an oper tors position for interconnecting the said telephonelines, of a link circuit at the said operators position, of a pluralityof sets of conductors tor the telephone system, one conductor of eachset being associated with each telephone line to numerically identifythe telephone line, a call distributing system to extend a calling teephone line to an instruction circuit on an operators position on theswitchboard and to extend a line identifying conductor under the controlof the said group of conductors identifying the telephone line to thesaid operators.

position, means to cause the said identitying conductor to be associatedwith a said link circuit to operate selective switches with which thesaid link circuit is associated whereby the said link circuit isconnected to a callng telephone line over a path independent oi the saidcall distributing system and instruction circuit, means thereafteroperative to dissociate the said link circuit and the said calldistributing system and instruction circuit, and connective means forthe said link circuit to interconnect the said link circuit with acalled telephone line.

8. In a telephone system, the combina- -tion with calling and calledtelephone lines,

of a plurality of groups of link circuits for interconnecting thecalling and called telephone lines of an instruction circuit for eachgroup of link circuits, call distributing means to extend a callingtelephone line to one of the said instruction circuits and a selectiveswitch system under the control of an operator for interconnecting amanually selected one of the link circu t associated with the saidinstruction circuit with the calling telephone line, the saidestablished connection being independent of the connection between thecalling telephone line and the said instruction circuit, lineidentityingmeans extended from the calling telephone line over the saidcall distributing system, an instruction circuit also contiplling thesaid selective switch systemT and a connection switch under the controlof the operator to connect the other end of the said link circuit with acalled telephone line to interconnect the called and calling telephonelines.

9. In a telephone system, the combination with calling and calledtelephone lines, of a plurality of groups of link circuit-s forinterconnecting the calling and called telephone lines, of aninstruction circuit for each group of link circuits, call distributingmeans to extend a calling telephone line to one of the said instructioncircuits and aselective switch system under the control of an operatorfor interconnecting a manually selected one of the link circuitsassociated with the said instruction circuit with the calling telephoneline, the said established connection being independent of theconnection between the calling telephone line and the said instructioncircuit, line identifying means extended from the calling telephone lineover the said call distributing system, an instruction circuit alsocontrolling the said selective switch system, a connection switch underthe control of the operator to connect the other end ot-the said linkcircuit with it called telephone line to interconnect the called andcalling telephone lines, and means operahle under the connection of thesaid calling telephone line and the said link circuit to dissociate thesaid link circuit and the said inst uction circuit.

ill. in abtelephoiw system, the comhinatiou with a plurality oftelephone lines one of which is a calling telephone line and one ofwhich is a called telephone line. an operators interconnecting linkcircuit for interconnecting the said calling and called telephone lines.means to extend a calling telephone line to the operators position atwhich the said link circuit. is located. an operators telephone set forthe said position, means to associate thoteleplione set with the saidcallin; line over the said calling line extension whereby the operatormay he instructed as to the desired called line. operator controlledmeans to ii'itcrconnect the called telephone line with the callingtelephone line over a conversational circuit entirely independent ol thecalling line extendingmeans. said interconnectingr means includin; amanually operated terminal and an automatically operated terminal. saidmanuallyv operated ter- 'n'iinal heine manually selectable, and adaptedto associate the said interconnectingmeans with the called telephoneline, and said automatically operated terminal being adapted to heactuated responsive to the manual selection of the said manuallyoperated terminal. 1

ll. in a telephone system, the combination with a plurality of telephonelines, one of which is a calling telephone line and one of which is acalled telephone line, an operator s intcrcomiecting link circuit forinter connecting: the said calling and called telephone lines, means toextend a calling telephone line: to the operators position at Which thesaid link circuit is located, an operators telephone set for the saidposition, means to associate the telephone set with tl said call- 'tothe desired called line, operator int-f line over the said calling lineextension whereby the operator may he instructed as controlled means tointerconnect the called telephone line with the calling telephone lineover a conversational circuit entirely indc: pendent of the calling lineextending means, an autrnnatically operated terminal and a manuallyoperated terminal for the said interconnecting means, said automatically,op-

erated terminal being selectedto interconnect the callingline with thesaid interconnecting means responsive to' the manual st lcction ol thesaid manually operated terminal, and means to interconnect the intercomnect-ingmeans to the called line by the oper- 'at ion of the manuallyoperated terminal, -the with a plurality oi telephone lincs, one ofwhich is a callin; telephone line and one of which is a called telephoneline", an operator-1s interconnectmg link circuit for interconnectingthe said calling and called telephone lines, means to extend a callingtelephone line to the operators position at which the said link circuitis located, an opera" tors telephone set for the said position, means toassociate the telephone set with the said calling line over the saidcalling line extension whereby the operator may be instructed as to thedesired called line, and operator controlled means to interconnect the:alled telephone line with the calling telephone line over aconversational circuit entirely independent of the calling lineextending incans, the said conversational circuit being under thecontrol of apparatus associated,\\'ith the calling telephone lineextending 1 11821115. and means thereafter to relieve theinterconnecting means of the said control. i

13. In a telephone system, aplurality of telephone lines leading fromsuhstations to an exchange, of call distributing apparatus at theexchange to extend a calling line to an operatoi"s idle call receivingcircuit, an operators link circuit adapted to interlinlr calling andcalled lines in conversational circuit, two groups of circuit conductorstor the lines, each gro ip containingr ten' circuit conductors, eachconductor representing a numerical digiha pair ot conductors adapted tobe associated with the said-groups at conductors, each oti the, saidpair leading: to a particular circuit conductor groups whereby the pairof circuit conductors may be identified by the numerical digitdesignations of group conductors with which they are connected, means toassociate the said pair of conductors with calling line apparatuswhereby the calling line may re; ccive a nun'ierical two digitaldesignation and a. relay serially included in circuit with the said pairof conductors the said coin ductors ot'. the groups connected thereto, acomniatating apparatus or the last-named ,condnctors together with asource of currentwhcrehy the said relay may he operated in acharacteristic manner, contacts for the said relay and acircuitconductor leading thru the said contacts and extended with theconductors of the line circuit to the said call receiving.circuit, andselective switching apparatus adapted to be associated with the saidcall receivingapparatus operating under the control of the said extendedcondaitor to directively establish acircaitconnection between thecalling line and operator's pendent. of the connection of the said calldistributing apparatus, and operator controlled means to extend theconnection from the said link circuit to the terminals of it calledtelephone line.

14. In a centrally operated telephone system, the combination with aplurality of telephone lines, of call instruction circuits for the saidlines, link circuits for establishinc, a connection between calling andcalled lines under :the control of apparatus in the said instruct-ioncircuits, a manually select able manual terminal for each of the saidlink circuits, and an automatically operable terminal for each of thesaid link circuits, said manual terminal controlling the said automaticterminah and automatic means responsive to the operation of the saidterminals to render the said interconnecting circuit and instructioncircuit independent.

15. in a centrally operated telephone system, the coml. ination with aplurality of telephone lines. of an operators instruction circuit forthe said lines. of an operators line interconnccting circuit having twoad justable terminals, one of the said terminals being a manuallyoperated terminal and the other terminal being automatically ope"- ated,and means operative under the joint control of the manually operatedterminal and the automatically operated terminal to connect the idinterconnecting circuit to :1 called line, and to operate the otheradjustable terminal to make connection with the calling line tointerconnect the calling and called line.

16. In a centrally operated telephone system, the conihination with aplurality of telephone lines, a circuit conductor adapted to he placedunder the control of line up paratus of any of the said lines, of anoperator's instruction circuit for the said lines, means to interconnecta calling line to the instruct-ion circuit. line idculil'ying meansadapted to he associated \ri'lh the said. calling line and the circuitconductor under the control ol' the said linc. an opera.- torsinterconnecting circuit having: a manual and an automatic adjustalilcterminal for called and calling lines. said automatic terminal hcingopcralcd over the said condoctor undcr the control of thc said lineidentifying means lonialqc connection with the calling line. and saidmanual terminal being under the control ol' the attendant operator.

1?. in a centrally operated telephone system, the combination with aplurality oi telephone lincs a circuit conductor adapted to he placedunder the control ol line up paratus ol'any ol the said lines. of anoperators instruction circuit for the said lines. means to interconnecta calling linc to the said instruction circuit, linc idcutilainp; meansadapted to be assocatcd with the said ,see

calling line and the circuit conductor under the control of t ue saidline, and an operators link circuit having an operator controlledterminal lor making connection with a called telephone line and anautomatic selective terminal for ma king connection with a callingtelephone line, said lastnamed terminal being under the control of thesaid line identifyin means over the said conductor.

18. in a centrally operated telephone system, the combination with aplurality of telephone lines, in an operatofs instruction circuit forthe id lines, means to interconnect a calling line to the saidinstruction circuit, line identifying means adapted to be associatedwith the said calling line and the circuit conductor under the controlof the said lineand an opcratous link circuit having. an operatorcontrolled terminal for making connection with :1 called telephone lineand an automatic selective terminal for making connection with a callingtelephone line, said last-named terminal being under the joint controlof the said line identityinp means over the said conductor and the saidoperator controlled terminal connection between the said link circuitand the sail called line.

19. in a centrally operated telephone system. he coinliinution with aplurality of telephone lines.v of cup oi call receiving cit h. cpeiatorsposition, oia rela nniulicr of interconnecting link the sa id opera torsposition, means line to one of the said ts, adjustable terminalscircuits to connecta calling call receiving? circui for each of the saidiinli circuits to connect the calling and called telephi'jine lines,operator controlled means to associate any incoming call circuit Witcircuits to control one oi the adjustable terminals for callingtelephone lines or the said iinl; circuit, said zissoclai ig neans beingopcratirc upon the adjustment of the called tcrininal uy the operator,and automatic means 'iciatc the said call receiving circuitiiie'cui callrcccii use oi ollu u cohnectirm l line, whereby the said um he availablefor the. ol' the system, and ad etwoen the said ilil l c lled ,clepnonclines associated c1 orcr the said link call receiving cirutcd telephonesysnhiuatmn with a plurality ol'tclcline in util'yin;- means for the innlines of a group of operator linl: circuits lo! intcrwmnccting urclutircly small group i coils for the said group g the said group ollink cirh any of the said link cuits and the said group of call circuitsbeing individual to an operators switchboard sec tion, means to causethe calls to be associated with the operators telephone set over thesaid call circuits, and means operative when the operator subsequentlyconnects a terminal of the said link circuit with 9. called telephoneline to cause, first, the other terminal of the said link circuit todirectively seek and connect with the calling telephone line under thecontrol of identifying means for the said telephone line operable over aconductor of thesaid instruction circuit, and

second, to thereafter dissociate the said instruction circuit and thesaid link circuit.

21. In a telephone system, a plurality of telephone lines, operatorspositions, link circuits thereat, each link circuit terminating at oneend of a manual switch and ter minating at'its other end in an automaticswitch, a rotary impulse. machine common to said lines and arranged totransmit impulses in accordance with the designation of any line whencalling, and means for causing an automatic switch to extend a selectedlink circuit to a calling line in response to selective impulses fromsaid impulse machine.

22. In a telephone system, a plurality of telephone lines, operatorspositions and link machine common to said lines and effective 3 toselectively operate an automatic switch of a selected link circuit underthe control of the calling line to cause said automatic switch to beconnected to a calling line responsive to the connection of said manualswitch to a wanted line. a

23. In a telephone system, a plurality of telephone lines, operatorspositions and link circuits associated therewith, said'link circuitseach being provided at one end with a manual switch, numericalautomatic. switches accessible to the other end of each link circuit,and a rotary impulse machine common to said lines and efi'ective toselectively operate the automatic switches "associated with a linkcircuit in response to impulses therefrom corresponding to thedesignation of the calling line, the operating of said numericalswitches being cont-rolled by the connection of a manual switch of alink 5 FRANK M. SLOUGH.

